#!/bin/bash
# Usage: script/brew-publish <name> <version> [<gh-project>]
#
# Updates the `<name>.rb` Homebrew formula to `<version>` and sends a pull
# request with the change.
set -e

brew_name="${1?}"
version="${2?}"

if ! type -p hub >/dev/null; then
  "ERROR: You have to install hub to proceed." >&2
  exit 1
fi

if [ -n "$3" ]; then
  gh_project="github.com/${3}"
else
  gh_project="$(git remote -v | grep '^origin' | grep -oE 'github.com[:/][^/]+/[^/ ]+' | head -1)"
  gh_project="${gh_project%.git}"
fi

url="https://${gh_project/:/\/}/archive/${version}.tar.gz"

checksum="$(curl -fsSL "$url" | shasum -a 256 -b | awk '{print $1}')"

if [ -z "$checksum" ]; then
  echo "ERROR: calculating the checksum failed for $url" >&2
  exit 1
fi

pushd "$(brew --prefix)"

git fetch -q origin master

branch="${brew_name}-${version}"
git checkout -q -B "$branch" origin/master

formula="Library/Formula/${brew_name}.rb"
sed -i.bak -E "
  s!^(  url ).+!\\1\"${url}\"!
  s!^(  sha256 ).+!\\1\"${checksum}\"!
" "$formula"
rm -f "${formula}.bak"

git commit -m "${brew_name} ${version#v}" -- "$formula"
# hackish way of getting the git remote name for user's fork
fork_remote="$(hub fork 2>&1 | grep -oE 'remote:? \S+' | tail -1 | awk '{print $2}')"
git push -u "$fork_remote" "$branch"
hub pull-request -m "${brew_name} ${version#v}"

git checkout -q -
